Clandeboye, home to the Marchioness of Dufferin and Ava, is filled with
memorabilia collected by the 1st Marquess, a 19th-century diplomat, and
provides a dramatic glimpse into his life.

As you pass between the cannons that flank its gates, Clandeboye seems to rise over the mist on the lake like a Chinese watercolour. This romantic early-Georgian mansion and its 2,000-acre estate in Co Down, Northern Ireland, is home to Lindy, the Marchioness of Dufferin and Ava, and is sustained by a series of enterprises. 'We are free of foundations and trusts,’ Lady Dufferin says proudly. Helping to keep the estate self-sufficient is its golf course, the Ava art gallery, a banqueting hall used for weddings, a classical music festival and Clandeboye’s own brand of yogurt, courtesy of the estate’s award-winning herd of Holstein and Jersey cows.

The settlement dates from the 17th century, but the building we see today was built in the early 1800s by Robert Woodgate (formerly an engineer to Sir John Soane), who was commissioned by the politician Sir James Blackwood, 2nd Baron Dufferin and Clandeboye. Incorporating elements of an earlier building, Woodgate created two wings at right angles to each other. About 50 years later, it became home to Frederick Hamilton-Temple-Blackwood, the 5th Baron and 1st Marquess of Dufferin and Ava (Lindy is the widow of the last Marquess, Sheridan; the title is now extinct). The great-grandson of the playwright Richard Sheridan, Frederick travelled widely as Governor-General of Canada and then Viceroy of India, and put his own stamp on Clandeboye.

Like many of his generation he was a passionate collector, and the interior at Clandeboye (sometimes known by its original name, Bally­leidy) is a reflection of the countries he served. The breadth of this passion is evident the moment one enters Clandeboye through its Doric portico. In the outer hall the walls are decorated with symmetrical displays of weaponry: daggers, pistols and cutlasses. In the pistachio-green Long Gallery there are more surprises. The grand staircase is flanked by a pair of narwhal tusks and on either side lie two ornate daybeds. These belonged to King Tibor of Burma. Frederick bought them when the contents of the palace at Mandalay were auctioned off after he annexed Upper Burma.

Upstairs the names of the bedrooms recall the many places that he served as a diplomat: France, St Petersburg, Canada, Rome. France is the most exquisite, decorated in neoclassical gilt motifs copied from a Pompeiian fresco. The mythological Europa and the bull are pictured on the bedhead. The gilt empire furniture complements the theme.

The house was designed to take maximum advantage of the light: the south-facing corner of the L-shaped layout is made up of 16 bay windows. Frederick also had a mania for glass roofing and skylights. The Simla corridor on the upper floor – named after the hill station in India where the British went on holiday – is illuminated by 'occulae’, small hemispherical skylights.

'Clandeboye needs constant attention,’ Lady Dufferin, a successful artist who works using her maiden name, Lindy Guinness, says. On the day I visited, the Rev Ian Paisley was scheduled to come and see a portrait she had painted of him. 'The studio is somewhere I feel safe,’ she says. Several chiaroscuro black-and-white gouaches in the studio, destined for a show in Paris, are studies of light in the rooms at Clandeboye – a subject she returns to often.

Outside is a walled garden with its thousands of saplings. It has been planted over the past 25 years by Conservation Volunteers Northern Ireland, which has brought Protestant and Catholic communities together to work in tandem. Deeper in the woods is Helen’s Tower, a turreted folly with views over the rolling parkland, immortalised in Tennyson’s poem of the same name. Commissioned by Frederick and completed in 1861, it was designed by the Scottish architect William Burn, its name in honour of Dufferin’s mother.

Lady Dufferin and her late husband, who died in 1988, have worked tirelessly to restore Clandeboye to its former glory and have created a lasting memorial to Frederick’s unique vision. It has been a major project, and the work continues. 'This is a real, living estate with no dead hand of institutional discipline,’ she says. 'I look upon Clandeboye as a gift.’